Growing Giant Delphinium Larkspur from Seeds in the UK
Delphinium Larkspur, commonly known as “Larkspur,” is renowned for its towering spires of elegant, tightly packed flowers that can reach heights of up to 36 inches. These majestic plants produce a stunning array of pastel shades including blue, pink, and white, adding a touch of sophistication and drama to any garden setting. Perfect for creating impressive backdrops in borders and along fences, these flowers bloom from mid-spring to early summer, offering long-lasting colour and beauty. The plants have a spread of about 12-18 inches, making them ideal for both large garden displays and smaller, more intimate garden spaces. Each packet contains over 50 seeds to plant & grow.
When to Sow UK Mixed Delphinium Larkspur Seeds
- Sowing Temperature: For optimal germination, maintain soil temperatures between 18-21°C (65-70°F). This temperature range ensures quick and even sprouting of seeds.
- Soil and Location: Select a location with fertile, well-drained soil that receives full sunlight or partial shade. Delphiniums prefer neutral to slightly alkaline soil (pH 6.5-7.5) enriched with organic compost.
- Seed Sowing Advice: Sow seeds at a depth of 1/8 inch. Keep the soil consistently moist but not waterlogged during the germination period.
Sowing Delphinium Larkspur Seeds in Spring
- Indoor Start: Begin indoors in late winter to early spring, around February to April, to get a head start on the growing season. This is particularly useful in regions with shorter growing periods or cooler springs.
- Outdoor Transplanting: Transplant seedlings outdoors when they are sturdy enough and the risk of frost has passed, typically from late May to June. Harden off seedlings before planting out to acclimatize them to outdoor conditions.
Growing Delphinium Larkspur in Summer
- Direct Sowing: In areas with a longer growing season, direct sowing outdoors can be done in early to mid-summer, around June to July. This timing is ideal for blooms in late summer to early autumn.
- Considerations: Ensure the soil is warm and there’s sufficient time for the plants to mature before the colder months. Summer sowing may require additional watering to keep the soil moist due to higher temperatures.
Growing Delphinium Larkspur in Autumn/Winter
- Overwintering: In milder UK regions, sowing in autumn for overwintering can yield an early bloom the following year. Sow directly in the ground in September or October.
- Protection: Provide protection with fleece or a cloche as temperatures drop to shield young plants from severe frost and ensure their survival over winter.
Caring for Delphinium Larkspur Plants & Seedlings
- Transplanting: When transplanting seedlings outdoors, space the plants 12-18 inches apart to allow for ample growth. Ensure the soil is well-drained and rich in organic matter.
- Maintenance: Keep the soil moist but not waterlogged. Delphiniums benefit from regular watering, especially during dry periods, to develop their full size and blooms.
- Companion Planting: Delphiniums pair well with other tall perennials and shrubs, adding height and interest to garden beds and borders.
- Support: Provide support for the tall flower spikes to prevent them from toppling over in strong winds or rain.
- Harvesting: Harvest the flowers when they are fully open for fresh arrangements or allow the seed pods to mature and dry for use in dried floral crafts.
- Weeding: Keep the area around Delphiniums free from weeds, which compete for nutrients and water. Gentle hand weeding is preferred to avoid disturbing the roots.
- Mulching: Applying a layer of organic mulch helps retain soil moisture, suppress weeds, and regulate soil temperature.
